Your first job is to create a set of criteria to establish a working definition of what might be considered a "behavior disorder".
In regards to the character Charlie Fineman, how would you classify his behavior? What sort of treatment should he be getting? What could you be doing for Charlie if you were his friend?

In my opinion, a behavior disorder is a type of behavior that is not parallel with society's standards. For example, a person screaming in the middle of the strret for no apparent reason is a behavorial disorder. It is also something that other people will find peculiar. In a society, there will always be a set standard like a standard of how much you are given attention, how much you can talk, how much you can shut out other people and so forth.
In the movie of Reign Over Me, the person with the behavior disorder, Charlie Fineman, suffers from social phobia. His disorders come from a traumatic experience which makes him shut out the world. We can see this in many parts of the movie such as the scene where he runs away from his parents and also when he first meets Alan. Charlie has a pretty bad case of social phobia because from the land-owners tells the Alan, no one has ever been in his apartment for 4 years. This is the main sign that Charlie does not want to interact with the outside world. It could also mean that Charlie has agroaphobia; a fear of going to a place where a traumatic experience occured. His fear of the 9/11 attacks prevent him from going out in society except for human needs such as food or laundry. However, a more concise disorder that most accurately defines Charlie's behavior disorder is Posttraumatic Stress Disorder or PTSD. The name explains itself. It is a disorder that disables many people of functioning properly because of a negative event that happened in the past. In Charlie's case, the 9/11 attacks that killed his family.
As for the the treatment, I believe he should try to socialize more so that he gains trust in society again which Alan does a nice job of. Alan invites Charlie back into the real world again. At first, it was not so good: all Charlie ever thought about was having fun with Alan. The point when Charlie realizes that he has a disorder is when Alan's father dies. Charlie wanted to have breakfast while Alan was confused by his reaction. As a friend, I would do what Alan does. I would try to bring him back and possible get him married again.